Motion and Motion and Design Lesson 6Design Lesson 6

Evaluating Vehicle Design: Evaluating Vehicle Design: Looking at Rubber Band Looking at Rubber Band

EnergyEnergy

MaterialsMaterials

Record Sheet 6-A: Evaluating Our Record Sheet 6-A: Evaluating Our Vehicle Design for Rubber Band Vehicle Design for Rubber Band Energy per studentEnergy per student

Standard Vehicle per groupStandard Vehicle per group 3 rubber bands per group3 rubber bands per group

OverviewOverview

Have explored the motion of your vehicles Have explored the motion of your vehicles when pulled by a weighted string.when pulled by a weighted string.

Will explore another way to move your Will explore another way to move your vehicle by releasing the energy stored in a vehicle by releasing the energy stored in a stretched rubber band and using it to turn stretched rubber band and using it to turn an axle.an axle.

Will test various ways your rubber band Will test various ways your rubber band can be used to move your vehicle.can be used to move your vehicle.

Will discuss the results of your evaluations.Will discuss the results of your evaluations.

BackgroundBackground Energy – capacity for doing workEnergy – capacity for doing work

Sources of energySources of energy Suns energy warms the Earth and enables Suns energy warms the Earth and enables

plants to grow.plants to grow. Wood and coal provide chemical energy that Wood and coal provide chemical energy that

is used for heating homes and businesses.is used for heating homes and businesses. Wind energy turns windmills and moves Wind energy turns windmills and moves

sailboats.sailboats. Our bodies use the energy stored in food.Our bodies use the energy stored in food. A flashlight uses energy stored in batteries.A flashlight uses energy stored in batteries. A car uses energy stored in gasoline.A car uses energy stored in gasoline.

Energy exists in many Energy exists in many forms.forms.

Stored energy or potential energy – energy ready to be Stored energy or potential energy – energy ready to be released.released.

In lesson 3, you stored energy in the weight on the string In lesson 3, you stored energy in the weight on the string when you raised it from the floor to the height of the when you raised it from the floor to the height of the work space.work space.

When you released the weight, gravity pulled it to the When you released the weight, gravity pulled it to the ground and the string pulled the vehicle along the work ground and the string pulled the vehicle along the work space. space.

As the weight descended, its stored energy was As the weight descended, its stored energy was converted to the energy of motion of both the weight and converted to the energy of motion of both the weight and the vehicle.the vehicle.

Physicists call the energy of motion kinetic energy.Physicists call the energy of motion kinetic energy.

In this lesson…In this lesson… Will evaluate the effectiveness of your vehicles’ Will evaluate the effectiveness of your vehicles’

design when it is driven by the energy stored in design when it is driven by the energy stored in a stretched rubber band.a stretched rubber band.

If you hold the ends of a rubber band and pull If you hold the ends of a rubber band and pull your hands slowly apart, the rubber band your hands slowly apart, the rubber band lengthens, but you can also feel it pulling your lengthens, but you can also feel it pulling your hands back in.hands back in.

When you wind the rubber band around the axle When you wind the rubber band around the axle of your vehicle, you store energy in the rubber of your vehicle, you store energy in the rubber band.band.

When store energy is released, it changes form.When store energy is released, it changes form.

Example of stored energyExample of stored energy When an archer pulls back on a bowstring, the bow When an archer pulls back on a bowstring, the bow

bends and the string stretches.bends and the string stretches.

The archer has stored energy in the bow and string.The archer has stored energy in the bow and string.

When the archer releases the arrow, the stored When the archer releases the arrow, the stored energy is transformed into the motion of the arrow. energy is transformed into the motion of the arrow.

Likewise, the wound-up rubber band on the Likewise, the wound-up rubber band on the vehicle’s axle has stored energy.vehicle’s axle has stored energy.

When you release your vehicle, the rubber band When you release your vehicle, the rubber band unwinds and the stored energy is converted to the unwinds and the stored energy is converted to the vehicle’s energy of motion.vehicle’s energy of motion.

You have observed how your vehicle can You have observed how your vehicle can move with rubber band energy.move with rubber band energy.

When you twisted the rubber band, the When you twisted the rubber band, the amount of energy stored in the rubber amount of energy stored in the rubber band increased.band increased.

When you released the vehicle, the When you released the vehicle, the stored energy caused the axel and the stored energy caused the axel and the attached wheels to spin and the vehicle attached wheels to spin and the vehicle to move.to move.

Getting Started Getting Started

Put on your goggles.Put on your goggles.

Get your standard vehicle.Get your standard vehicle.

Get the connected rubber bands.Get the connected rubber bands.

Take a couple of minutes to explore Take a couple of minutes to explore how you might use the connected how you might use the connected rubber bands to move your vehicle.rubber bands to move your vehicle.

Do the investigation and Do the investigation and complete the sheet.complete the sheet.

DiscussionDiscussion

What did you feel in your hand as you What did you feel in your hand as you wound the rubber band?wound the rubber band?

Did this feeling change as you wound Did this feeling change as you wound the rubber band tighter? If so, how?the rubber band tighter? If so, how?

Did the direction in which you wound Did the direction in which you wound the rubber band affect the direction in the rubber band affect the direction in which your vehicle traveled? If so, which your vehicle traveled? If so, how?how?

DiscussionDiscussion What did you do to make your What did you do to make your

vehicles move a longer distance?vehicles move a longer distance?

What did you do to make your What did you do to make your vehicles move a shorter distance?vehicles move a shorter distance?

Do you know why this happened?Do you know why this happened?

Return materials. Do not Return materials. Do not disassemble your vehicle. disassemble your vehicle.

ExtensionsExtensions

Bring in advertisements for automobiles Bring in advertisements for automobiles and trucks. Prepare your own and trucks. Prepare your own advertisement promoting the special advertisement promoting the special features of one of these vehicles.features of one of these vehicles.

Conduct research to find out how the Conduct research to find out how the design of the automobile has changed design of the automobile has changed over time. Create a timeline to show over time. Create a timeline to show these changes. these changes.

The End!!!The End!!!